Several methods are known in the art for joining tissue portions at the site of organ resections, particularly gastrointestinal (GI) tract resections, or at the site of other types of tissue perforations or tissue openings. These include threads for manual suturing, staplers for mechanical suturing, tissue adhesives and compression rings and clips.
While manual suturing is universally known and relatively inexpensive, the degree of success depends considerably on the skill of the surgeon. Another disadvantage of this technique is that post-operative complications are common. Further, suturing an organ results in lack of smoothness of the tissue therein, which, when the sutured organ is part of the gastrointestinal tract, hampers peristalsis in the sutured area. Finally, suturing is both labor and time consuming.
Increasingly, stapling is being used for suturing. Staplers for mechanical suturing ensure a reliable joining of tissue and reduce the time needed for surgery compared with manual suturing. However, after healing, metal staples remain in place along the perimeter of the suture, which reduces elasticity of the junction and adversely affects peristalsis when the sutured organ is part of the gastrointestinal tract. These complications often lead to strictures and inflammatory reactions to the foreign bodies left behind. Staples also often lead to undesired leakage of blood and other body liquids into the region of resected tissue further resulting in severe infection. Additionally, stapling mechanisms generally are relatively large and fairly rigid, limiting the maneuverability of an endoscope used in conjunction with the stapling mechanism. This lack of maneuverability restricts an endoscopic approach to many locations within the body.
Junctions using compression devices, such as rings (or loops) and clips, ensure the best seal and post-operative functioning of the organs. The compression force exerted by compression rings is applied only momentarily at the tissue junction and is reduced as the tissue is crushed. Clips made of memory alloys enable portions of tissue to be pressed together with increasing pressure as they are heated, due to the inherent properties of the alloys. Their design is cheap and they are small in size. Moreover, when used in the GI tract they are often self-evacuated.
A major disadvantage of known clips is that they permit compression of only approximately 80-85% of the junction perimeter, thus requiring additional manual sutures, which reduce the integrity of the seal of the junction during the healing period and its elasticity during the post-operative period. Furthermore, this additional suturing is problematic inasmuch as it has to be carried out across a joint which includes a portion of the clip, thereby rendering difficult the sealing and anastomosis of the organ portions.
The compressive force exerted by clips generally is not equal at both ends of the clip because of the clips' typically asymmetric construction. Similarly, compression does not act along a line between the two compressing portions holding the tissue to be compressed. This can lead to the clip disengaging from the closure site before closure is complete and scar tissue mature.
Typically, clips do not necessarily have a securing mechanism against slipping off the tissue. Clips as currently designed may also affect the maneuverability of an endoscope.